Process for obtaining isophorone

Abstract

The present invention relates to a process for obtaining isophorone from acetone, characterized in that the operation is carried out (i) in liquid phase in the presence of a magnesium aluminum double oxide of formula Mg 1-x Al x O 1+x or (ii) either in gaseous or liquid phase in the presence of a catalyst of general formula (I): (Mg.sup.2+).sub.1-x (Al.sup.3+).sub.x (OH.sup.-).sub.2 !.sup.x+ (OH - ) x ! x- (H 2 O) n (I) with 0.20≦x≦0.33 and n<1.

We claim: 
     
       1. A process for obtaining isophorone from acetone, characterized in that the operation is carried out (i) in liquid phase in the presence of a magnesium aluminum double oxide of formula Mg 1-x  Al x  O 1+x  or (ii) either in gaseous or liquid phase in the presence of a catalyst of general formula (I):    (Mg.sup.2+).sub.1-x (Al.sup.3+).sub.x (OH.sup.-).sub.2 !.sup.x+  (OH.sup.-).sub.x !.sup.x- (H.sub.2 O).sub.n              (I)     with 0.20≦x≦0.33 and n<1.   
     
     
       2. The process according to claim 1, characterized in that the value of n is between about 0.48 and about 0.75, the limits included. 
     
     
       3. The process according to claim 1, characterized in that the value of n is between about 0.48 and about 0.61, the limits included. 
     
     
       4. The process according to claim 1, characterized in that the liquid acetone and the catalyst are in contact at a temperature of between about 100° C. and 250° C. 
     
     
       5. The process according to claim 4, characterized in that the temperature is between about 110° C. and about 220° C. 
     
     
       6. A liquid phase process for obtaining isophorone from acetone which comprises: contacting the liquid acetone with a solid catalyst comprising a magnesium aluminum double oxide of formula   Mg.sub.1-x Al.sub.x O.sub.1+x ;     and     recovering a product consisting essentially of isophorone, unreacted acetone and by-products;   wherein 0.20≦x≦0.33.   
     
     
       7. The process according to claim 6, wherein x is about 0.3. 
     
     
       8. The process according to claim 6, wherein the process is carried out continuously. 
     
     
       9. The process according to claim 8, wherein the liquid acetone passes through a stationary bed comprising the catalyst. 
     
     
       10. The process according to claim 8, wherein the liquid acetone contacts a stirred bed comprising the catalyst. 
     
     
       11. The process according to claim 6, wherein the process is carried out noncontinuously. 
     
     
       12. The process according to claim 11, wherein the liquid acetone and the catalyst are in contact for a reaction period of from 30 minutes to 8 hours. 
     
     
       13. The process according to claim 12, wherein the reaction period is from 1 hour to 4 hours. 
     
     
       14. The process according to claim 6, characterized in that the liquid acetone and the catalyst are in contact at a temperature of between about 100° C. and 250° C. 
     
     
       15. The process according to claim 14, characterized in that the temperature is between about 110° C. and about 220° C. 
     
     
       16. The process according to claim 6, wherein the process further comprises separating the solid catalyst from the product. 
     
     
       17. The process according to claim 16, wherein the method of separating is filtration. 
     
     
       18. The process according to claim 6, wherein the process further comprises separating isophorone from the unreacted acetone and the by-products. 
     
     
       19. The process according to claim 18, wherein the method of separating is selected from distillation and settling. 
     
     
       20. A process for obtaining isophorone from acetone which comprises: contacting the acetone with a solid catalyst comprising a compound of general formula (I):    (Mg.sup.2+).sub.1-x (Al.sup.3+).sub.x (OH.sup.-).sub.2 !.sup.x+  (OH.sup.-).sub.x !.sup.x- (H.sub.2 O).sub.n              (I);     and     recovering a product consisting essentially of isophorone, unreacted acetone and by-products;   wherein 0.20≦x≦0.33 and n<1.   
     
     
       21. The process according to claim 20, characterized in that the acetone is present in a gaseous phase. 
     
     
       22. The process according to claim 20, characterized in that the acetone is present in a liquid phase. 
     
     
       23. The process according to claim 22, wherein the process is carried out continuously. 
     
     
       24. The process according to claim 23, wherein the liquid acetone passes through a stationary bed comprising the catalyst. 
     
     
       25. The process according to claim 23, wherein the liquid acetone contacts a stirred bed comprising the catalyst. 
     
     
       26. The process according to claim 22, wherein the process is carried out noncontinuously. 
     
     
       27. The process according to claim 26, wherein the liquid acetone and the catalyst are in contact for a reaction period of from 30 minutes to 8 hours. 
     
     
       28. The process according to claim 27, wherein the reaction period is from 1 hour to 4 hours. 
     
     
       29. The process according to claim 20, wherein the catalyst comprises a meixnerite compound of formula:    (Mg.sup.2+).sub.0.75 (Al.sup.3+).sub.0.25 (OH.sup.-).sub.2 !.sup.0.25+  (OH.sup.-).sub.0.25 !.sup.0.25- (H.sub.2 O).sub.0.5.     
     
     
       30. The process according to claim 20, wherein the process further comprises preparing the solid catalyst by a process selected from the group consisting of: mixing a magnesium aluminum double oxide with water in the absence of CO 2  to form a mixture, stirring the mixture, forming a hydrated solid, separating the solid from the mixture, and drying the solid, wherein the magnesium aluminum double oxide has the formula   Mg.sub.1-x Al.sub.x O.sub.1+x wherein 0.20≦x≦0.33;     and     calcining a hydrotalcite to form a magnesium aluminum double oxide, mixing the magnesium aluminum double oxide with water in the absence of CO 2  to form a mixture, stirring the mixture, forming a hydrated solid, separating the solid from the mixture, and drying the solid, wherein the magnesium aluminum double oxide has the formula   Mg.sub.1-x Al.sub.x O.sub.1+x wherein 0.20≦x≦0.33.       
     
     
       31. The process according to claim 20, wherein the process further comprises separating the solid catalyst from the product. 
     
     
       32. The process according to claim 31, wherein the method of separating is filtration. 
     
     
       33. The process according to claim 20, wherein the process further comprises separating isophorone from the unreacted acetone and the by-products. 
     
     
       34. The process according to claim 33, wherein the method of separating is selected from distillation and settling.